/*
 * Copyright 2002-2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.validation;

import java.beans.PropertyEditor;

import org.springframework.beans.BeanUtils;
import org.springframework.beans.ConfigurablePropertyAccessor;
import org.springframework.beans.PropertyAccessorUtils;
import org.springframework.beans.PropertyEditorRegistry;

/**
 * Abstract base class for {@link BindingResult} implementations that work with
 * Spring's {@link org.springframework.beans.PropertyAccessor} mechanism.
 * Pre-implements field access through delegation to the corresponding
 * PropertyAccessor methods.
 *
 * @author Juergen Hoeller
 * @since 2.0
 * @see #getPropertyAccessor()
 * @see org.springframework.beans.PropertyAccessor
 * @see org.springframework.beans.ConfigurablePropertyAccessor
 */
public abstract class AbstractPropertyBindingResult extends AbstractBindingResult {

    /**
    * Create a new AbstractPropertyBindingResult instance.
    * @param objectName the name of the target object
    * @see DefaultMessageCodesResolver
    */
    protected AbstractPropertyBindingResult(String objectName) {
        super(objectName);
    }


    /**
    * Returns the underlying PropertyAccessor.
    * @see #getPropertyAccessor()
    */
    public PropertyEditorRegistry getPropertyEditorRegistry() {
        return getPropertyAccessor();
    }

    /**
    * Returns the canonical property name.
    * @see org.springframework.beans.PropertyAccessorUtils#canonicalPropertyName
    */
    protected String canonicalFieldName(String field) {
        return PropertyAccessorUtils.canonicalPropertyName(field);
    }

    /**
    * Determines the field type from the property type.
    * @see #getPropertyAccessor()
    */
    public Class getFieldType(String field) {
        return getPropertyAccessor().getPropertyType(fixedField(field));
    }

    /**
    * Fetches the field value from the PropertyAccessor.
    * @see #getPropertyAccessor()
    */
    protected Object getActualFieldValue(String field) {
        return getPropertyAccessor().getPropertyValue(field);
    }

    /**
    * Formats the field value based on registered PropertyEditors.
    * @see #getCustomEditor
    */
    protected Object formatFieldValue(String field, Object value) {
        PropertyEditor customEditor = getCustomEditor(field);
        if (customEditor != null) {
            customEditor.setValue(value);
            String textValue = customEditor.getAsText();
            // If the PropertyEditor returned null, there is no appropriate
            // text representation for this value: only use it if non-null.
            if (textValue != null) {
                return textValue;
            }
        }
        return value;
    }

    /**
    * Retrieve the custom PropertyEditor for the given field, if any.
    * @param field the field name
    * @return the custom PropertyEditor, or <code>null</code>
    */
    protected PropertyEditor getCustomEditor(String field) {
        String fixedField = fixedField(field);
        Class targetType = getPropertyAccessor().getPropertyType(fixedField);
        PropertyEditor editor = getPropertyAccessor().findCustomEditor(targetType, fixedField);
        if (editor == null) {
            // editor = BeanUtils.findEditorByConvention(targetType);
        }
        return editor;
    }


    /**
    * Provide the PropertyAccessor to work with, according to the
    * concrete strategy of access.
    * <p>Note that a PropertyAccessor used by a BindingResult should
    * always have its "extractOldValueForEditor" flag set to "true"
    * by default, since this is typically possible without side effects
    * for model objects that serve as data binding target.
    * @see ConfigurablePropertyAccessor#setExtractOldValueForEditor
    */
    public abstract ConfigurablePropertyAccessor getPropertyAccessor();

}
